The Fairmount Line (once the New Haven Railroad's freight line into its South Boston yards) has been a commuter route for a long time now, in one form or another since 1979, and the current shuttle operation dates back to 1987. But in recent years there has been a big push to promote it as quasi-rapid transit for the Dorchester neighborhoods through which it runs, and this free ride window is part of that promotion.

I will second TN and mention the Dorchester Branch was the route used when the SouthwestCorridor project was constructed during the 1980s by Amtrak and MBTA commuter trains.This line was a good alternate route into BOS and evolved into today's Fairmount Line.

MACTRAXX

EXPRESS TRAIN TO NEW YORK PENN STATION-NO JAMAICA ON THIS TRAIN-PLEASE STAND CLEAR OF THE CLOSING TRAIN DOORS

Members of Congress are sometimes judged by how much federal money they bring back to their district. But US Representative Michael Capuano is taking a more direct route.

In an unusual bid to boost ridership on the Fairmount Line, which runs through Dorchester, Mattapan, and Roxbury on its way downtown, the congressman is donating $53,000 in campaign funds to the MBTA to subsidize free trips on the commuter rail line from May 8 to May 21.

“I’ve never heard of any such use of campaign funds before and I’ve been doing this work for 20 years,” said Paul S. Ryan, a vice president at Common Cause, an advocacy group that promotes best practices in government. “But just to be perfectly clear, there are no legal problems with it.”

FWIW, Capuano's doing this because Fairmount is the only rail schedule self-contained entirely within his 7th Congressional District. It's an unusual use of campaign funds for sure, but not all that out-of-character given how much he cracks the whip at state officials on GLX (project area also self-contained in his district). He serves on the House Transpo/Infrastructure committee, Transit subcommittee, and Railroads subcommittee.

Past rumors of him mulling a Gov. run in '18 have cooled considerably now that party control of the U.S. House may be up for grabs next term. He's second in line for the Financial Services Chairmanship on the D side, which is worth way more political capital than Governor of the Commonwealth. So odds are overwhelming he's staying put. If staying put his campaign warchest is so massive and reelection so guaranteed that it's pocket change to buff his committee cred with this quirky award.

I rode the old Midland daily while the SW Corridor was under construction, but at that time there were no stops between Cleary Sq. (current Fairmount?) and South Station. I've got two busy weekends coming up, but railfanning Mattapan - Ashmont is also on my list.